1. Field of the Invention
The present invention relates to a solid-state image sensing device.
2. Description of the Related Art
To photograph a scene in colors using a solid-state image sensor, a plurality of color images of the scene are taken by the solid-state image sensor to produce a plurality of image signals corresponding to the color images. The image signals are synthesized to produce a television-type color image signal. Being exposed to an optical image through color filters of three primary colors of red (R), green (G) and blue (B), for example, the solid-state image sensor converts the optical image to three image signals corresponding to R, G and B. The image signals are synthesized and applied to a color television monitor, thereby displaying a color image of the scene.
In conventional solid-state image sensors, a plurality of photoelectric conversion members, each formed of a large number of photoelectric elements vertically arranged, are arrayed in parallel in the horizontal direction, and vertical transfer members are disposed adjacent to and in parallel with the respective photoelectric conversion members. The photoelectric conversion members each convert an incident optical image to an electric signal, and the vertical transfer members each store photoelectric signals from a corresponding photoelectric conversion member and sequentially transfer the photoelectric signals in the vertical direction. A horizontal transfer member is provided below the array of the vertical transfer members to store the photoelectric signals transferred from the vertical transfer members and to sequentially transfer the photoelectric signals in the horizontal direction.
With the conventional color solid-state image sensors, three color filters of R, G and B are attached to three consecutive photoelectric conversion members, respectively, and photoelectric signals from the three photoelectric conversion members are synthesized to form a color image signal. Thus, three photoelectric conversion members are needed to obtain an image for a vertical column, lowering the resolution of the whole image obtained by the solid-state image sensor.
As an alternative to the above system, a plane-sequential system is known. In this system, a light source adapted for emitting R, G and B light is switched to sequentially emit the R, G and B light for illumination of a scene, and three-color photoelectric signals sequentially output from the solid-state image sensor are synthesized to produce a color image signal. According to this system, since a photoelectric conversion member can produce a color image signal corresponding to one vertical column, the resolution will not be degraded. With this system, however, since three images of R, G and B are sequentially taken to obtain a color image, color dislocations would occur in the resultant image. Further, when the subject is a rapidly moving subject, R, G and B images are displaced to one another.